Support plate for semiconductor components

ABSTRACT

The present invention relates to a support plate ( 1 ), preferably made from glass, granite or ceramic, for supporting components ( 3 ), in particular ICs or other semiconductor components. The top face of the support plate ( 1 ) is at least partially roughened (roughened areas ( 2 )), resulting in a roughness Ra of preferably about 0.3 micrometer. Further, the present invention relates to a packaging unit ( 4 ) comprising the support plate ( 1 ).

The present invention relates in a first aspect to a support plate forsupporting at least one component, in particular a wafer, on the topface of said support plate. In a further aspect, the present inventionrelates to a method for the preparation of said support plate. In aneven further aspect, the present invention relates to a packaging unitcomprising said support plate. In a still further aspect, the presentinvention relates to the use of said support plate, the use of saidpackaging unit and the use of a non-corrosive, non-contaminatingmaterial.

In the IC packaging and semiconductor industry, components are usuallypackaged in and/or supported by plastic materials. A problem that oftenoccurs when using plastics for packaging and/or supporting components isthat the plastics contain plasticizers and, optionally, other auxiliaryingredients that may diffuse from the plastics onto the componentsresulting in contamination of the components. In some cases thisdiffusion of plasticizers or other auxiliary ingredients even causes thecomponents to be adhered to the plastic materials.

The above problem is particularly pertinent in the case of IC andsemiconductor components, as it very important to avoid contamination ofthese components. As a result, the components often have to be cleanedagain after storage on or in the plastic materials, even if anappropriate protection against the environment is secured. It goeswithout saying that this is highly undesirable.

A further problem that often occurs when using small IC andsemiconductor components, in particular when the components have a thinsheet-like design, such as in the case of wafers, is that, when suchcomponents are applied on a substantially smooth and flat support (suchas e.g. a slide for spectroscopic analysis), the formation of an ‘aircushion’ between the support and the component to be supported is likelyto occur. As a result the component will tend to float on, and in somecases away from, the support. Therefore, it is difficult to obtain aprecise and unambiguous positioning of the component on the support.

However, if eventually a suitable positioning of the component on thesupport has been achieved the components may tend to stick (e.g. underinfluence of the Van der Waals forces) to the support. It goes withoutsaying that this sticking is highly undesired as it results in anineffective way of working and therefore in a considerable loss of time.

In the prior art it has been proposed to provide sucking holes insupports to enable IC and other semiconductor components to be sucked tothe support. In this respect reference is made to the following twopatent applications.

EP-A-1,091,400 describes a wafer probe comprising a ceramic substrateand a conductor layer formed on the surface thereof. On the surface ofthe ceramic substrate of the wafer probe channels may be formed, thechannels being provided with air suction holes.

The abstract of Japanese application 60-095148 (publication no.:61-252642) describes a chip supporting table for testing semiconductorIC chips. The chips are firmly held on the work table as they are suckedwith a vacuum through sucking holes.

It is an object of the present invention to avoid one or more of theabove-mentioned or other problems.

It is a further object of the present invention to avoid the need ofsuction holes and associated vacuum suction equipment which must beinstalled, maintained, repaired, energized, etc.

It is a still further object of the present invention to provide asupport plate for supporting at least one component, in particular an ICor other semiconductor component, more particular a wafer, on whichsupport plate the component may be positioned precisely andunambiguously.

It is a further object to provide a method for the preparation of asupport plate according to the invention.

It is an even further object to provide a packaging unit comprising saidsupport plate.

Furthermore, it is an object of the present invention to provide for theuse of said support plate, the use of said packaging unit and the use ofa non-corrosive, non-contaminating material for supporting and storingcomponents, in particular IC and other semiconductor components, moreparticular wafers.

One or more of the above objects are achieved by a support plateaccording to the present invention for supporting at least onecomponent, in particular an IC or other semiconductor component, moreparticular a wafer, on a top face of said support plate, characterizedin that the top face of the support plate is at least partiallyroughened.

The support plate according to the present invention provides in asurprisingly simple and cost-effective manner for a contamination-free,precise and unambiguous positioning of the component on the supportplate.

Generally, the support plate may be any substantially flat plate, suchas a worktop, a slide for spectroscopic analysis, etc.

The whole top face of the support plate may be roughened. Instead, onlycertain areas may be roughened.

The components to be supported may be any component, preferably thecomponents are ICs or other semiconductor components. Even morepreferably, the components are small, substantially flat sheet-likecomponents such as a wafer.

Advantageously, the at least partially roughened top face of the supportplate has a roughness Ra in the range of 0.10-3.0 μm, preferably in therange of 0.20-2.0 μm, even more preferably in the range of 0.25-1.0 μm,most preferably about 0.3 μm. It has been shown that these roughnessesallow for a precise and unambiguous positioning of the component on thesupport plate.

Even more preferably, the top face of the roughened support platecomprises a groove or a pattern of grooves, the at least one groovepreferably preventing or at least minimizing the formation of an ‘aircushion’ between the top face and the at least one component. Herewithit is prevented that the component will float on, or even away from, thesupport.

The person skilled in the art will readily understand how to design thegroove or pattern of grooves in order to achieve the desired effect.Generally, any groove or pattern of grooves may be used, as long as theformation of an ‘air cushion’ between the top face of the support plateand the component to be supported by the support plate is prevented orat least minimized.

It has been shown that very effective positioning results may beachieved if the at least one groove has a depth of about 0.20 mm.

According to a preferred embodiment, the top face of the roughenedsupport plate comprises at least one recess for at least partiallyreceiving the component to be supported. Herewith, the positioning ofthe component is further improved. The person skilled in the art willreadily understand that the recess may have any suitable form in orderto receive and accommodate the component to be supported. If desired,two or more recesses may be provided to receive more than one component.

Although the support plate may be made from any suitable material, thesupport plate is made from a non-corrosive, non-contaminating material.Herewith it is prevented that the component is contaminated, such as isthe case when using plastics for packaging or supporting components.

According to the present invention by “a non-corrosive,non-contaminating material” is meant any material that does not causedeterioration of the component to be supported or packaged.

More preferably, the support plate is made from a material selected froma group of materials comprising glass, granite and ceramic (includingtechnical ceramic) and a combination thereof, more preferably thematerial is glass, most preferably transparent glass. All types of glass(e.g. soda lime glass, borosilicate glass [Pyrex®], etc.), granite andceramic may be used.

In a further aspect the present invention relates to the use of thesupport plate according to present invention as a slide forspectroscopic analysis. As the top face of the slide is roughened asoutlined above, the component may be easily and precisely positioned onthe top face, without the tendency to float away from the slide. Afterthe component on the slide has been submitted to the spectroscopicanalysis, such as X ray analysis, the component may be easily removedfrom the slide, if desired using a pair of tweezers or the like, withoutthe tendency to stick to the slide. Usually the slide will be made froma transparent material such as glass.

In this respect it is preferred that the top face of the slide has aroughness such that, during spectroscopic analysis, no interferencecaused by the roughness of the top face of the slide occurs. The personskilled in the art will readily understand how to choose the roughnessof the top face of the slide to prevent such interference.

In an even further aspect, the present invention relates to a method forthe preparation of a support plate for supporting at least onecomponent, in particular an IC or other semiconductor component, moreparticularly a wafer, on a top face of said support plate, characterizedby the steps of:

-   -   forming the support plate; and    -   roughening the top face of the formed support plate at least        partially using powder blasting, such that the at least        partially roughened top face of the support plate has a        roughness Ra in the range of 0.10-3.0 μm, preferably in the        range of 0.20-2.0 μm, even more preferably in the range of        0.25-1.0 μm, most preferably about 0.3 μm.

It has been surprisingly shown that the use of powder blasting toroughen the top face of the support results in high-accuracy mechanicaletching of the supports according to the present invention. Furthermore,powder blasting has shown to be a very versatile technique. If desired,masks may be used to obtain a particular pattern of roughened andnon-roughened areas on the top face of the support plate.

As the method of powder blasting is known as such it is not necessary toillustrate the method in further detail. In this respect reference ismade to e.g. Slikkerveer, P. J. et al., “High quality mechanical etchingof brittle material by powder blasting”, Eurosensors XIII, The 13thEuropean Conference on solid-state transducers, Sep. 12-15, 1999, TheHague, The Netherlands, pp. 655-662.

In an even further aspect, the present invention relates to a packagingunit for packaging at least one component, in particular an IC componentor other semiconductor component, more particularly a wafer, said thepackaging unit comprising a support plate according to the invention.

The person skilled in the art will readily understand that the packagingunit may have any suitable form, shape or design. For example, thepackaging unit may be a Petri dish, wherein the lower dish is thesupport plate and the upper dish seals the at least partially roughenedlower dish.

According to a preferred alternative embodiment, the packaging unitfurther comprises a cover plate having a bottom face facing the top faceof the support plate, the bottom face of the cover plate being at leastpartially roughened and being releasably connectable to the top face ofthe support plate.

According to a further alternative embodiment, the top face of thesupport plate and the bottom face of the cover plate each comprise atleast one recess, which recesses are designed to at least partiallyreceive a component to be packaged.

Furthermore, the present invention relates to the use of the packagingunit for storage of components, in particular IC ore other semiconductorcomponents, more particularly wafers.

Finally, the present invention relates to the use of a non-corrosive,non-contaminating material, preferably selected from the groupcomprising glass, granite and ceramic and a combination thereof, morepreferably glass, most preferably transparent glass in the packaging ofICs or other semiconductor components, in particular wafers. It has beenshown that the use of the above-mentioned materials, in particularglass, avoids the problem of contamination of the components to bestored.

These and other aspects of the present invention will be apparent fromand elucidated with reference to the embodiment(s) describedhereinafter.

Hereinafter the present invention will be illustrated in more detail bya drawing. Herein shows:

FIG. 1 a schematic top view of the support plate according to thepresent invention;

FIG. 2 an enlarged schematic top view of the support plate according tothe present invention in the form of a slide;

FIG. 3 a schematic top view of a first embodiment of the packaging unitaccording to the present invention comprising the support plateaccording to FIG. 1;

FIG. 4 a schematic cross-sectional view of the packaging unit accordingto FIG. 3; and

FIG. 5 a schematic top view of a second embodiment of the packaging unitaccording to the present invention.

Identical reference numbers indicate similar structural components.

FIG. 1 shows a schematic top view of a disk shaped support plate 1 madefrom glass. On the top face of the support plate 1 a pattern ofroughened areas 2 is formed. The areas 2 have a roughness Ra of about0.3 μm. Furthermore the areas 2 are recessed with respect to the topface of the support plate 1, the recesses having a depth of 0.5 mm. Onthe roughened surface of some of the areas 2, components 3 are placed.

The roughened areas 2 have been obtained by powder blasting the top faceof the support plate 1 using a mask.

FIG. 2 shows an enlarged schematic top view of a slide 21 made fromtransparent glass. The top face of the slide 21 comprises a plurality ofstuds 22 projecting from the top face of the slide 21. The top side ofthe studs 22 has been roughened to obtain a roughness Ra of about 0.3μm.

On the top face of the slide 21 a pattern of grooves 23 is presentseparating the studs 22. The grooves 23 serve to prevent, or at leastminimize, the formation of an ‘air cushion’ between the top face of thestuds 22 of the slide 21 and the one component (not shown) to be placedon the slide 21. Furthermore, the slide 21 comprises a through hole 24,which hole 24 can be penetrated by a pin of a spectroscopic analyzer(not shown) to firmly attach the slide 21.

The component can be easily positioned on the slide 21 without the riskof floating away from the slide 21. Also, the component can afterwardsbe removed from the slide 21, without the tendency to adhere to theslide 21.

FIG. 3 shows a schematic top view of a first embodiment of a packagingunit 4. The packaging unit 4 comprises the support plate 1 as shown inFIG. 1, the components 3 placed on the roughened areas 2, a furthertransparent disk 5 (cf. FIG. 4) and connectors 6, such as clamps orclips, in order to releasably connect the support plate 1 to the furtherdisk 5.

As can be clearly seen from FIG. 4, the disk 5 is placed on the supportplate 1.

Finally, FIG. 5 shows a schematic top view of a second embodiment of thepackaging unit 4, in which the support plate 1 and the cover plate 5 arearranged next to each other for illustrative purposes. In this case, thesupport plate 1 and the cover plate 5 are rectangular in shape.

In the embodiment of FIG. 5 the cover plate 5 is provided with roughenedprojecting areas 7 (Ra˜0.3) which are complementary to the recessedareas 2. Instead the projections 7 may be recessed, such that therecesses 2 and 7 form a cavity to at least partially receive a component3 to be packaged.

The person skilled in the art will understand that many modificationsmay be made without departing from the scope of the appended claims. Forinstance, the packaging unit may be in the form of a Petri dish,comprising a lower and upper disk, wherein the lower disk may contain,on the top face thereof, roughened areas. Further, the lower disk of thePetri dish may be used as a slide.

1. Support plate for supporting at least one component, in particular anIC or other semiconductor component, more particularly a wafer, on a topface of said support plate, characterized in that the top face is atleast partially roughened.
 2. Support plate according to claim 1,wherein the at least partially roughened top face of the support platehas a roughness Ra in the range of 0.10-3.0 μm, preferably in the rangeof 0.20-2.0 μm, even more preferably in the range of 0.25-1.0 μm, mostpreferably about 0.3 μm.
 3. Support plate according to claim 1, whereinthe top face comprises a groove or a pattern of grooves, the at leastone groove preferably preventing or at least minimizing the formation ofan ‘air cushion’ between the top face and the at least one component. 4.Support plate according to claim 3, wherein the at least one groove hasa depth of about 0.20 mm.
 5. Support plate according to claim 1, whereinthe top face comprises at least one recess for at least partiallyreceiving the at least one component.
 6. Support plate according toclaim 1, wherein the support plate is made from a non-corrosive,non-contaminating material.
 7. Support plate according to claim 1,wherein the support plate is made from a material selected from a groupof materials comprising glass, granite and ceramic and a combinationthereof, more preferably glass, most preferably transparent glass. 8.Use of the support plate according to claim 1 as a slide forspectroscopic analysis.
 9. Use according to claim 8, wherein the topface of the slide has a roughness such that, during spectroscopicanalysis, no interference caused by the roughness of the top face of theslide occurs.
 10. Method for the preparation of a support plate forsupporting at least one component, in particular an IC or othersemiconductor component, more particularly a wafer, on a top face ofsaid support plate, characterized by the steps of: forming the supportplate; and roughening the top face of the formed support plate at leastpartially using powder blasting such that the at least partiallyroughened top surface of the support plate has a roughness Ra in therange of 0.10-3.0 μm, preferably in the range of 0.20-2.0 μm, even morepreferably in the range of 0.25-1.0 μm, most preferably about 0.3 μm.11. Packaging unit for packaging at least one component, in particularan IC or other semiconductor component, more particularly a wafer, saidpackaging unit comprising a support plate according to claim
 1. 12.Packaging unit according to claim 11, wherein the packaging unit furthercomprises a cover plate having a bottom face facing the top face of thesupport plate, the bottom face of the cover plate being at leastpartially roughened and being releasably connectable to the top face ofthe support plate.
 13. Packaging unit according to claim 10, wherein thetop face of the support plate and the bottom face of the cover plateeach comprise at least one recess, which recesses are designed to atleast partially receive the at least one component to be packaged. 14.Use of the packaging unit according to claim 11 for storage ofcomponents, in particular ICs or other semiconductor components, moreparticularly wafers.
 15. Use of a non-corrosive, non-contaminatingmaterial, preferably selected from the group comprising glass, graniteand ceramic and a combination thereof, more preferably glass, mostpreferably transparent glass, in the packaging of ICs or othersemiconductor components, in particular wafers.